Recently, in silver halide photographic materials, in particular, photographing photosensitive materials, the demand is increasing for a super high-speed photosensitive material as represented by films of I.S.O. 1600 and a photosensitive material high in image quality and sharpness that is suitable for a small format camera such as a disk camera and a camera for 110 size.
Hitherto, it is known that as one of means for improving sharpness and graininess a compound that will release a development inhibitor correspondingly to the density of the image when development is carried out, which compound will be referred to as a "DIR compound" hereinafter, is contained in a silver halide color photographic material.
Generally, the DIR compounds are of the type that will release a development inhibitor when they react with the oxidized product of an aromatic primary amine developing agent, and typical examples of such DIR compounds are so-called DIR couplers in which a group is introduced on the coupling position thereof, which group can form a compound having a development inhibiting effect when it is released from the coupling position at the time of the coupling of the coupler (e.g., compounds disclosed in U.S. Pat. Nos. 3,227,554, 3,701,783, 4,095,984, 4,149,886, 3,933,500, 4,146,386, and 4,477,563). The DIR coupler is a compound that can form a dye from the coupler moiety as a result of a coupling reaction with the oxidized product of an aromatic primary amine developing agent while releasing a development inhibitor.
Examples of compounds that can form colorless dyes as a result of a coupling reaction with the oxidized product of an aromatic primary amine developing agent while releasing a development inhibitor are compounds disclosed, for example, in U.S. Pat. Nos. 3,632,345, 3,928,041, 3,958,993, 3,961,959, and 4,052,213, and Japanese Patent Application (OPI) Nos. 110529/78 and 13333/79 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application").
Examples of so-called DIR hydroquinones that can release a development inhibitor as a result of a cross oxidation reaction with the oxidized product of a developing agent are compounds disclosed in U.S. Pat. Nos. 3,379,529 and 3,930,863.
However, these compounds are disadvantageous in that desensitization will take place, the function will lower due to the decomposition during the storage of the film after the application of the compound, or the effect for improving sharpness is unsatisfactory.
Examples of compounds whose splitting-off group will release a development inhibitor in a timed manner when coupled with the oxidized product of an aromatic primary amine developing agent are compounds disclosed in U.S. Pat. No. 4,248,962 and Japanese Patent Application (OPI) No. 56837/82.
When these compounds are used, since the effect of the inhibition can be exhibited at a position a certain distance away from the development silver halide grains, it has been assumed that sharpness would be improved due to the adjacency effect, but since the timing for releasing a splitting-off group is unsatisfactory these compounds have not improved sharpness. During the storage of the films, the compounds cannot avoid hydrolysis or cleavage under high humidity conditions, and therefore problems such as desensitization or lowering of the function occur.
To overcome these problems, Japanese Patent Application No. 33059/84 (corresponding to European Patent 0,157,146A2) discloses compounds that release a photographically useful group such as a development inhibitor by the coupling reaction with a developing agent oxidized product that will result in releasing a compound that will in turn undergo an oxidation-reduction reaction with another molecule of the developing agent oxidized product.
It is certain that the photosensitive materials containing, of these compounds, a compound that releases a development inhibitor in the end are excellent in storage stability and the sharpness has been improved. However, it has disadvantageously been found that if the compound is used in a large amount for a silver halide contained in the emulsion layer containing the compound, the development inhibiting effect is too high to lower the sensitivity excessively, or to make the adjustment of the gradation remarkably difficult, or the compound that is released after the reaction of the developing agent oxidized product and can react with another molecule of the developing agent oxidized product adversely affects to lower the sensitivity, or the sharpness is adversely affected due to the undesirable adjacency development effect by the part that reacts with the developing agent oxidized product.
On the other hand, compounds partly similar to those that will be obtained by excluding the development inhibitor part from the present compounds are disclosed in Japanese Patent Application (OPI) No. 138636/82 and U.S. Pat. No. 4,477,560. These compounds are completely different from the present compounds in that, as a constituent for scavenging the color development agent oxidized product, only the split-off part acts, and therefore as claimed in U.S. Pat. No. 4,477,560, a large amount, that is, from 1 to 5% mol, of the compound to be added for the silver halide contained in the same photosensitive emulsion layer is required, and if a large amount is added the desensitization effect is not high inview of photographic performance. In contrast therewith, if the present compound is added in such a large amount, remarkable desensitization would take place.